Is there any proof, that Theodore Ayrault Dodge made those illustrations himself? There are there are no specifications on who drafted them in the book. Neither on the cover, nor in the preface, at the table of content or at the end of the book. If Ayrault did not make those illustrations, they are perhaps not in the public domain. Because the artist may not be dead longer than 70 Years.
In fact in many countries the whole book would not be in the public domain under those conditions. In most european-countries copyright-law requires ALL artists, who have created artwork for a Publication, to be dead for 70 Years, before the work becomes public domain.